If the Securities and Exchange Commission were to adopt reforms similar to what’s been put in place in other countries, dark-pool volume may drop by half, according to the CEO of Liquidnet. Liquidnet is one of several so-called “dark pools” that allow buyers and sellers to place trades anonymously, allowing big investors to buy and sell without moving the broader market.

Seth Merrin, who also founded the firm, spoke to MarketWatch after reaching a settlement with the agency over disclosing information about firms that trade in the dark pool to prospective new clients. Liquidnet paid a $2 million fine. “We went to our membership and we acknowledged there were holes in our processes and procedures,” Merrin said. The SEC did not find evidence that Liquidnet’s disclosures financially harmed any of its clients, and the CEO said the company’s new procedures require firms to opt into any new initiatives.

He also spoke about the speech delivered Thursday by Mary Jo White, the SEC’s chairwoman, about market structure. White said she’s instructed the agency’s staff to work on proposals.

Merrin says the SEC can look at what’s been done in Australia, Canada and Europe for advice. In Canada, dark venues are required to execute in blocks of at least 5,000 shares. In Australia and Europe, dark venues are required to give meaningful price improvement from what’s available on listed exchanges. If the SEC adopts one of these models, “half the volume would flow back to the lit exchanges,” he said.

Merrin says dark venues that just internalize orders — that is, take them from their clients — don’t add value. “We’re a size discovery venue,” Merrin says of his firm. “That’s complimentary to an exchange and a good innovation.”

He added if there were rules that would require execution in size or in the midpoint, that would take away much of the volume for high-frequency traders operating within dark pools.